Field of the Invention
The present invention relates to enzyme compositions and methods of degrading or converting cellulosic material with the enzyme compositions.
Description of the Related Art
Cellulose is a polymer of the simple sugar glucose linked by beta-1,4 bonds. Many microorganisms produce enzymes that hydrolyze beta-linked glucans. These enzymes include endoglucanases, cellobiohydrolases, and beta-glucosidases. Endoglucanases digest the cellulose polymer at random locations, opening it to attack by cellobiohydrolases. Cellobiohydrolases sequentially release molecules of cellobiose from the ends of the cellulose polymer. Cellobiose is a water-soluble beta-1,4-linked dimer of glucose. Beta-glucosidases hydrolyze cellobiose to glucose.
The conversion of lignocellulosic feedstocks into ethanol has the advantages of the ready availability of large amounts of feedstock, the desirability of avoiding burning or land filling the materials, and the cleanliness of the ethanol fuel. Wood, agricultural residues, herbaceous crops, and municipal solid wastes have been considered as feedstocks for ethanol production. These materials primarily consist of cellulose, hemicellulose, and lignin. Once the cellulose is converted to glucose, the glucose is easily fermented by yeast into ethanol.
There is a need in the art to improve cellulolytic protein compositions through supplementation with additional enzymes to increase efficiency and to provide cost-effective enzyme solutions for degradation of lignocellulose.
WO 2004/056981 discloses a partial cellobiohydrolase from Myceliophthera thermophila. WO 2008/008070 discloses a cellobiohydrolase from Chrysosporium lucknowense. WO 94/021785 discloses a Family 10 xylanase from Aspergillus aculeatus. Ustinov et al., 2008, Enzyme and Microbial Technology 43: 56-65, disclose a Family 10 xylanase from Myceliophthera thermophila. 
The present invention relates to improved enzyme compositions for degrading or converting cellulosic material.